绝对路径
<form id="formSubmit" action="${pageContext.request.contextPath}/findall"
${pageContext.request.contextPath}==========<%=path%>就是在 下面server里面path路径1 /hao_hao   2  为空
 <Context docBase="hao_hao" path="/" reloadable="true" source="org.eclipse.jst.jee.server:hao_hao"/>
http://localhost:8080/hao_hao/ ===============<%=basePath%>   1 /hao_hao====<%=path%>
http://localhost:8080/         ===============<%=basePath%>   2  为空             ====<%=path%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>                   http              ://         localhost         :         8080            /hao_hao+/ 
